Bought a low mileage Alpha that has SynJex in which is supposedly close to the Ctech 2 oil. I’m switching it back to Ctech. My question for everyone is can you mix the two oils in the reservoir, or do I need to drain all of the old oil out? Had the same issue last year on a 2018 Mtn Cat but ended up draining all the old due to the fact the chaincase needed to be replaced then took to the dealer and had them bleed the oil system